Identification Documents
Identification documents (hereafter “ID documents”) play a critical role in today's society. One example of an ID document is an identification card (“ID card”). ID documents are used on a daily basis—to prove identity, to verify age, to access a secure area, to evidence driving privileges, to cash a check, and so on. Airplane passengers are required to show an ID document during check in, security screening and prior to boarding their flight. In addition, because we live in an ever-evolving cashless society, ID documents are used to make payments, access an automated teller machine (ATM), debit an account, or make a payment, etc.
(For the purposes of this disclosure, ID documents are broadly defined herein, and include, e.g., credit cards, bank cards, phone cards, passports, driver's licenses, network access cards, employee badges, debit cards, security cards, visas, immigration documentation, national ID cards, citizenship cards, social security cards, security badges, certificates, identification cards or documents, voter registration cards, police ID cards, border crossing cards, legal instruments, security clearance badges and cards, gun permits, gift certificates or cards, membership cards or badges, etc., etc. Also, the terms “document,” “card,” “badge” and “documentation” are used interchangeably throughout this patent application.).
Many types of identification cards and documents, such as driving licenses, national or government identification cards, bank cards, credit cards, controlled access cards and smart cards, carry certain items of information which relate to the identity of the bearer. Examples of such information include name, address, birth date, signature and photographic image; the cards or documents may in addition carry other variable data (i.e., data specific to a particular card or document, for example an employee number) and invariant data (i.e., data common to a large number of cards, for example the name of an employer). All of the cards described above will be generically referred to as “ID documents”.
FIGS. 1 and 2 illustrate a front view and cross-sectional view (taken along the A-A line), respectively, of an identification (ID) document 10. In FIG. 1, the ID document 10 includes a photographic image 12, a bar code 14 (which may contain information specific to the person whose image appears in photographic image 12 and/or information that is the same from ID document to ID document), variable personal information 16, such as an address, signature, and/or birthdate, and biometric information 18 associated with the person whose image appears in photographic image 12 (e.g., a fingerprint, a facial image or template, or iris or retinal template), a magnetic stripe (which, for example, can be on a side of the ID document that is opposite the side with the photographic image), and various security features, such as a security pattern (for example, a printed pattern comprising a tightly printed pattern of finely divided printed and unprinted areas in close proximity to each other, such as a fine-line printed security pattern as is used in the printing of banknote paper, stock certificates, and the like).
Referring to FIG. 2, the ID document 10 comprises a pre-printed core 20 (also referred to as a substrate). In many applications, the core can be a light-colored, opaque material (e.g., TESLIN (available from PPG Industries), polyvinyl chloride (PVC) material, polyester, polycarbonate, etc.). The core 20 is laminated with a transparent material, such as clear PVC or polyester material 22, which, by way of example, can be about 1-5 mil thick. The composite of the core 20 and clear laminate material 22 form a so-called “card blank” 25 that can be up to about 30 mils thick. Information 26a-c is printed on the card blank 25 using a method such as Laser Xerography or Dye Diffusion Thermal Transfer (“D2T2”) printing (e.g., as described in commonly assigned U.S. Pat. No. 6,066,594, which is incorporated hereto by reference in its entirety.) The information 26a-c can, for example, comprise variable information (e.g., bearer information) and an indicium or indicia, such as the invariant or nonvarying information common to a large number of identification documents, for example the name and logo of the organization issuing the documents. The information 26a-c may be formed by any known process capable of forming the indicium on the specific core material used.
To protect the information that is printed, an additional layer of transparent overlaminate 24 can be coupled to the card blank and printed information, as is known by those skilled in the art. Illustrative examples of usable materials for overlaminates include biaxially oriented polyester or other optically clear durable plastic film.
“Laminate” and “overlaminate” include, but are not limited to film and sheet products. Laminates used in documents include substantially transparent polymers. Examples of laminates used in documents include polyester, polycarbonate, polystyrene, cellulose ester, polyolefin, polysulfone, and polyamide. Laminates can be made using either an amorphous or biaxially oriented polymer. The laminate can comprise a plurality of separate laminate layers, for example a boundary layer and/or a film layer.
The degree of transparency of the laminate can, for example, be dictated by the information contained within the identification document, the particular colors and/or security features used, etc. The thickness of the laminate layers can vary and is typically about 1-20 mils. Lamination of any laminate layer(s) to any other layer of material (e.g., a core layer) can be accomplished using a lamination process.
In ID documents, a laminate can provide a protective covering for the printed substrates and provides a level of protection against unauthorized tampering (e.g., a laminate would have to be removed to alter the printed information and then subsequently replaced after the alteration.). Various lamination processes are disclosed in assignee's U.S. Pat. Nos. 5,783,024, 6,007,660, 6,066,594, and 6,159,327. Other lamination processes are disclosed, e.g., in U.S. Pat. Nos. 6,283,188 and 6,003,581. Each of these U.S. patents is herein incorporated by reference.
The material(s) from which a laminate is made may be transparent, but need not be. Laminates can include synthetic resin-impregnated or coated base materials composed of successive layers of material, bonded together via heat, pressure, and/or adhesive. Laminates also includes security laminates, such as a transparent laminate material with proprietary security technology features and processes, which protects documents of value from counterfeiting, data alteration, photo substitution, duplication (including color photocopying), and simulation by use of materials and technologies that are commonly available. Laminates also can include thermosetting materials, such as epoxy.
In a typical ID document, one or more laminate layers are joined together with the substrate, possibly including other security devices, such as holograms, integrated circuits, optical memory, RFID tag, etc. to form a complete document. These laminate layers are designed to enhance the durability and security of the identification documents. From the standpoint of durability, the laminate should increase the document's ability to withstand wear and tear experienced in the field, including heat and humidity that can compromise the integrity of the document structure.
From the standpoint of security, the laminate should be difficult to remove to prevent or at least evidence tampering.
Some ID documents use laminates that are made from a polyester outer layer and a polyolefin hot melt sealant. Because these are different materials, bonding them requires a primer or tie coat layer prior to sealant application. The bond between the polyester and adhesive layers are compromised when exposed to heat and humidity resulting in a document that prematurely fails in the field.
A security challenge is to design laminates for document structures that are difficult to separate from the substrate. For example, some document structures use a thermoplastic sealant to bond polyester film laminates to a document core. This bonding process is subject to a de-laminating attack, where the attacker heats the document in an attempt to separate the laminate from the core. The activation temperature at which the laminate and sealant moves is quite different in some structures, and this characteristic can enable an attacker to remove the laminate without destruction of the document or visible evidence of tampering.
The invention provides laminates for documents, laminated documents and methods for making both laminates and the laminated documents. One aspect of the invention is a polyester laminate for a document. It is formed from different polyester materials to produce a polyester laminate having desired durability and bonding properties. One of the polyester materials provides a durability property. Another of the polyester materials provides a layer having a bonding property for bonding the laminate directly to a core layer without requiring an adhesive.
In one embodiment, the polyester material providing the durability comprises PCTA copolyester, and the polyester material with the bonding property comprises PETG copolyester. In this case, the polyester material with the bonding property is selected to enable direct bonding to a core layer of TESLIN or polyester through a roll to roll or platen press process. The polyester materials are selected to remove the weak link between the laminate and adhesive used to bond it to the core. By creating a laminate containing similar materials, there is no separate adhesive interface between the laminate and core. The polymer chains intermingle, and thus, the polyester laminate requires no adhesive, eliminating the adverse effect of heat and humidity on the interface between the laminate and core layers. Further, the polyester laminate addresses the problem of separation attacks. By using two polyester materials in which the activation temperature are close to one another, the addition of heat causes the destruction of the entire document.
Additional aspects of the invention include methods for making the laminate. The laminate may be made by joining separate polyester materials with desired durability and bonding properties in variety of methods, such as roll to roll, extrusion coating, coextrusion, platen press, and injection/extrusion molding processes.
Additional aspects of the invention include laminated documents and methods for making the laminated documents.
Of course, the drawings are not necessarily drawn to scale, with emphasis rather being placed upon illustrating the principles of the invention. In the drawings, like reference numbers indicate like elements or steps. Further, throughout this application, certain indicia, information, identification documents, data, etc., may be shown as having a particular cross sectional shape (e.g., rectangular) but that is provided by way of example and illustration only and is not limiting, nor is the shape intended to represent the actual resultant cross sectional shape that occurs during manufacturing of identification documents.